Injection pump drives



Oct. 14, 1958 w. H. HIMES' INJECTION PUMP DRIVES Filed Aug. 19, 1953 ONE-WAY ONE-POINT CLUTCH INVEN TOR. W\LL|AM H. HIMES United States Patent INJECTION PUMP DRIVES William H. Himes, McAlester, Okla.

Application August 19, 1953, Serial No. 375,312

' 1 Claim. 01. 123-439 (Granted under Title 35, U. S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to diesel engines and is particularly directed to means to prevent backfiring in such engines. Most internal combustion engines, including diesel type engines, will backfire if either the intake or exhaust ports are open when an explosion takes place, or if either port is open before fuel burning ceases. When such engines are used to drive hoist or lift trucks in handling explosives the danger of sparks or flames about the engine becomes obvious.

An object of this invention is to provide means for preventing backfiring in internal combustion engines.

A more specific object of this invention is to provide improved means for shutting off the fuel supply when the engine operates in reverse.

Other objects will become apparent from the following description of one embodiment of this invention. The invention is defined with particularity in the appended claim and is illustrated in the accompanying drawing in which:

Figure 1 is a sectional diagrammatic view of a diesel engine embodying the invention,

Figure 2 is a sectional assembled view of a one-way, one-point clutch employed in the diesel engine of this invention, and

Figure 3 is an exploded perspective view of the clutch of Figure 2.

The steps involved in each cycle of operation of a diesel engine include (1) intake of fresh air through the intake port; (2) compression of the fresh air; (3) injection of fuel pressure and explosion; and, (4) expulsion of exhaust gases. The intake port is normally opened by a cam driven from the crank shaft and in normal forward operation the intake port is closed at the instant the combustion stroke commences. At the end of the compression stroke and when the pressure is the highest, the fuel is injected and combustion starts. Should the crank at this point be forced to revolve in the reverse direction as by an overload on the engine, the intake port is apt to open and expel ignited fuel into the intake manifold and hence into the air cleaner structure. When the air cleaner is of the oil bath type flames usually result.

In Fig. 1 is shown diagrammatically the cylinder 1 of an internal combustion engine with the piston 2 coupled through the connecting rod 3 to the crank shaft 4. The intake and exhaust ports 5 and 6, respectively, are closed by valves which are operated in the usual manner from cam shafts, not shown, driven by the crank shaft. Fuel is injected to the upper end of the cylinder in the 4-cycle engine depicted, from the injection nozzle 7 coupled through the high pressure line 8 to the fuel pump 9. Ball valves in the ports of the fuel drive fuel from the supply line 10 under pressure into the high pressure line 8, The piston 11 of the fuel pump is usually coupled one-way, one-point clutch 15. Because of thisclutch,

power can be transmitted from the crank shaft to the fuel injection pump only while the crank-shaft is rotating in its normal forward direction. If the crank shaft and the power take-01f shaft should reverse direction because of improper timing or becauseof a stalling load on the engine, the fuel injection pump will not follow. Accordingly, power for the injection of fuel stops the instant reverse rotation commences. r

Because the rotational position relationship of the injection pump shaft and the engine crank shaft must be fixed for proper synchronization of fuel injections with piston travel, the clutch 15 must permit the driving and driven shafts of the clutchto return to their original posi-, tions each time the clutch is operated. Means, not shown, is provided for effecting the necessary fine timing adjustments of the injection pump. Because the clutch must be of the one-point type a single pawl and detent must be used in the clutch.

One clutch which has been found to be well balanced dynamically in spite of the asymmetry of the one-point structure is shown in Figs. 2 and 3. The principal elements of the particular clutch shown comprise the disk 20 keyed on or machined integrallywith the driven shaft 12a. In the periphery of the disk is fitted a radially retractable pawl 21, the pawl being biased axially by the coil spring 22. The disk 20 runs inside the ring 23, the ring having an axial thickness slightly greater than the disk 20 and an inside diameter sufiicient to clear the outer edge of the disk 20. On the inner periphery of the ring is formed a single detent 24 to receive the toe of the pawl 21. Secured to oppositevfaces of the ring are plates 25 and 26, the inner surfaces of the plates being machined and ground to accurately fit the ring and its enclosed disk 20. Ball bearings 27 are preferably installed between the shaft 12a and the plates 25 and 26 for low friction operation.

A universal joint is preferably employed to couple the driver shaft 14 to the clutch housing. Conveniently, the joint comprises a fiber washer 28 bolted at alternate points along its periphery to the collar 29 on the driven shaft and through bolts 30 to the clutch housing.

The weight and moment of inertia of the pawl may be 7 made, by proper design, approximately equal to the moment of inertia of the diametrically opposite segment of the disk for proper dynamic balance to the normal operating speed of the clutch.

In operation, power from the driving shaft 14 is transmited through the universal coupling 28 and 29 to the clutch housing. Rotation of the housing is imparted to the disk 20 and its keyed shaft 12a through the engaged pawl 21 and detent 24. Should the direction of rotation of the driving shaft reverse, the pawl leaves its detent with negligible torque and rotate freely without disturbing the driven shaft 12a. The internal combustion engine of this invention will not inject fuel into the cylinders during reverse rotation and will prevent backfiring. The oneway, one-point clutch is easy to make and to install in conventional diesel engines between the power take-off shafts and injection pump shafts, and is reliable in operastruct ion without departingfrom the spirit of the invencam shaft to be rotated in said one direction in response tion, as particularly defined intheappended claim. Oneway, one-point clutches, for example, of dilferent design may serve to prevent reverse rotation of thefuel injection pump;

* Whatis claimed is:

lnkcombination withan internal combustion engine with cooperating piston and valves, a fuel injection pump, a crankshaft-driven by said engine and rotatable in either directioma cam shaft operatively connected to said crankshaft and having a cam secured thereto and rotatable therewith foroperating said pump to inject fuel under pressure intothe cylinder of the engine in timed relation with respect to the operation of the piston and valves, theimprovement'comprising a one-way, one-point clutch member disposed between said shafts for rigidly connecting saidsh'aftsin a single predetermined angular relationship to cause fuel to be pumped only when said crankshaft is-rot'ated in one direction and comprising a pair of mutually spacedplates, a ring disposed between said plates, securing means for said plates and ring, means connecting said crankshaft to said plates and ring for impartingrotative movement thereto, a disk carried by said cam shaft "and disposed between said plates and within said ring; a single notch formed in the inner periphery of saidr-ing, a radially movable pawl carried'by said disk-and normally in engagement with said notch for releasably locking said disk to the ring and causing said to rotation-of the crankshaft in-- that direction;-said-ring being adapted to actuate said pawl to release said disk as the ring is rotated in reverse direction by the crankshaft thereby to prevent further rotation of said cam shaft and operation of the pump by the cam, and yieldable means disposed within said disk and having one end thereof in abutting engagement with said pawl and the other end in abutting engagement with the disk for yieldably urging and maintaining the pawl in locking engagement with said notch until the ring'is rotated in said reverse direction by the crankshaft.

References Cited'in the file of this patent UNITED STATESPATENTS 305,635 Schinneller Sept. 23, 1884 444,341 Egg Jan. 6, 1891 651,422 Lerch June 12, 1900 1,918,075 Woolson July 11, 1933 1,985,934 Logan Jan. 1, 1935 2,024,486 Thompson Dec. 17, 1935 2,323,353 Plog July 6, 1943 FOREIGN PATENTS 97,373 Sweden Nov. 14, 1939 233,437 Switzerland Oct. 16, 1944 1,059,724 France Nov. 10, 1953 161,916 Australia Mar. 14, 1955 

